IRAM and Gaia views of multi-episodic star formation in IC 1396A The origin and dynamics of the Class 0 protostar at the edge of an HII region
Author
Sicilia-Aguilar, AuroraPatel, Nimesh
Fang, Min

Roccatagliata, Veronica
Getman, Konstantin
Goldsmith, Paul
Affiliation
Univ Arizona, Dept AstronIssue Date
2019-02-07Keywords
stars: protostarsphoton-dominated region
stars: individual: IC 1396A-PACS-1
stars: individual: HD 206267
open clusters and associations: individual: Tr37
molecular data
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EDP SCIENCES S ACitation
Sicilia-Aguilar, A., Patel, N., Fang, M., Roccatagliata, V., Getman, K., & Goldsmith, P. (2019). IRAM and Gaia views of multi-episodic star formation in IC 1396A-The origin and dynamics of the Class 0 protostar at the edge of an HII region. Astronomy & Astrophysics, 622, A118.Journal
ASTRONOMY & ASTROPHYSICSRights
© ESO 2019.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Context. IC 1396A is a cometary globule that contains the Class 0 source IC 1396A-PACS-1, which was discovered with Herschel. Aims. We use IRAM 30m telescope and Gaia DR2 data to explore the star formation history of IC 1396A and investigate the possibilities of triggered star formation. Methods. IRAM and Herschel continuum data were used to obtain dust temperature and column density maps. Heterodyne data reveal the velocity structure of the gas. Gaia DR2 proper motions for the stars complete the kinematics of the region. Results. IC 1396A-PACS-1 presents molecular emission similar to a hot corino with warm carbon chain chemistry due to the UV irradiation. The source is embedded in a dense clump surrounded by gas at velocities that are significantly different from the velocities of the Tr 37 cluster. CN emission reveals photoevaporation, while continuum data and high-density tracers ((CO)-O-18, HCO, DCO+, and N2D+) reveal distinct gaseous structures with a range of densities and masses. Conclusions. By combining the velocity, column density, and temperature information and Gaia DR2 kinematics, we confirm that the globule has experienced various episodes of star formation. IC 1396A-PACS-1 is probably the last intermediate-mass protostar that will form within IC 1396A; it shows evidence of being triggered by radiation-driven implosion. Chemical signatures such as CCS place IC 1396A-PACS-1 among the youngest known protostars. Gaia DR2 data reveal velocities in the plane of the sky similar to 4 km s(-1) for IC 1396A with respect to Tr 37. The total velocity difference (8 km s(-1)) between the Tr 37 cluster and IC 1396A is too small for IC 1396A to have undergone substantial rocket acceleration, which imposes constraints on the distance to the ionizing source in time and the possibilities of triggered star formation. The three stellar populations in the globule reveal that objects located within relatively close distances (<0.5 pc) can be formed in various star-forming episodes within similar to 1-2 Myr. Once the remaining cloud disperses, we expect substantial differences in evolutionary stage and initial conditions for the resulting objects and their protoplanetary disks, which may affect their evolution. Finally, evidence for short-range feedback from the embedded protostars, and in particular, the A-type star V390 Cep, is also observed.Note
Open access journal.ISSN
0004-63611432-0746
Version
Final published versionAdditional Links
https://www.aanda.org/10.1051/0004-6361/201833207ae974a485f413a2113503eed53cd6c53
10.1051/0004-6361/201833207